1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to an LCD device including a module assembly.
2. Discussion of the Related Art
In general, since flat panel display devices are thin, light weight, and have low power consumption, they are increasingly being used in portable devices. Among the various types of flat panel display devices, liquid crystal display (LCD) devices are widely used for laptop computers and desktop monitors because of their superiority in resolution, color image display, and display quality.
LCD devices use the optical anisotropy and polarization properties of liquid crystal molecules to generate a desired image. In particular, liquid crystal molecules can be aligned in a specific orientation, which can be controlled by applying an electric field across the liquid crystal molecules. Due to optical anisotropy, incident light is refracted according to the orientation of the liquid crystal molecules, thereby generating the desired image.
Specifically, an LCD device have upper and lower substrates with electrodes formed thereon and the substrates are spaced apart and facing each other with a liquid crystal material interposed therebetween. When a voltage is applied to the electrodes and generates an electric field across the liquid crystal material, an alignment direction of the liquid crystal molecules changes in accordance with the applied voltage. As a result, light transmittance through the liquid crystal material is varied and images are formed.
Most LCDs are passive devices in which images are displayed by controlling an amount of light input from an outside light source. Thus, a separate light source (i.e., backlight device) is generally employed for irradiating an LCD device. There are two types of backlight devices, an edge type and a direct type, based on an arrangement of a light source within the device. In particular, an edge type backlight device has a light source installed at a side portion of a light guiding plate, and a direct type backlight device includes a light source installed above a reflective plate.
FIG. 1 is a schematic cross-sectional view of a liquid crystal display module having an edge type backlight device according to the related art, and FIG. 2 is partially enlarged view showing an electrostatic inrush to a driving IC of the liquid crystal display module of FIG. 1. In FIG. 1, a liquid crystal display module includes a backlight assembly 10 and a liquid crystal panel 20 disposed above the backlight assembly 10. The backlight assembly 10 includes a lamp 11 at its edge, a light guide plate (not shown) next to the lamp 11, a lamp housing (not shown) surrounding the lamp 11, and a reflector (not shown) underneath the light guide plate. The backlight assembly 10 and the liquid crystal panel 20 are held together by a top case 30 and a bottom case 40. In particular, the top case 30 is coupled with the bottom case 40 to accommodate and fasten the backlight assembly 10 and the liquid crystal panel 20. In general, the top and bottom cases 30 and 40 are formed of a metallic material.
In addition, a printed circuit board (PCB) 50, a driving IC 60 and a connecting tab 70 are disposed between the backlight assembly 10 and the top and bottom cases 30 and 40. The PCB 50 is disposed underneath the backlight assembly 10, and the connecting tab 70 is disposed around the lamp 11. The connecting tab 70 is often referred to as a tape carrier package (TCP), and the driving IC 60 is formed on the connecting tab 70. In particular, the connecting tab 70 connects the PCB 50 to the driving IC 60 and connects the driving IC 60 to the liquid crystal panel 20.
However, the metallic top case 30 directly contacts the liquid crystal panel 20 without other additional connectors. As shown in FIG. 2, such a contact generates static electricity and causes electrostatic discharge (ESD) affecting the driving IC 60 or other circuitry. In particular, the static electricity flows through the metallic conductive top case 30 and then is discharged into the adjacent electric circuits, such as the driving IC 60. As a result, the electrostatic discharge (ESD) damages the driving IC 60, thereby causing malfunctions in the liquid crystal panel 20.